To grow good sweet corn it requires plenty of space, to gain rapid growth, moisture and nutrients. Corn should not be planted into cold, wet soil as such conditions encourage fungi, which can rapidly rot the seeds.
Almost any soil suits sweet corn provided that it has been well manured. The soil should be dug to a spade’s depth and add half a bucketful of compost and manure to the sq. yd. A couple of days before planting, rake into the top inch of soil some peat substitute to lighten up the soil a little adding fish manure at 4 oz. (120g) to the sq.yd.
To get the corn off to a good start, sow the seeds into seed compost that is warm and moist during March. It helps germination if the seed is first soaked in water for about 4 hours prior to sowing.
Sow two seeds in the centre of a 2-in (50mm) pot then thin down to one plant per pot if both seeds germinate. The pot should stand on staging in the greenhouse at a temperature of 55 deg F. (13 deg C.) water when necessary.
Early May begin to harden off by putting the plants out into a cold frame. Plant out in late May or early June depending on your location. To aid pollination, plant in 2 by 1 ft. (30cm) rectangles rather than in rows.
If you do not have a greenhouse the seeds can be sown where they are to grow out in the open in 2 by 1 ft. (30cm) stations in late May. As before plant two seeds per station to begin with, later only one should be allowed to develop.
To give a little protection cut down clear plastic mineral bottles can be placed over the top until the seedlings are about 3 in (76mm) high.
Earth up the plants when they are about 1 ft. (30cm) high so that they will produce stronger roots that will give them more support as they grow. Keep them well watered and give a mulch to retain moisture.
Do not remove the tassels at the top of the plant; these constitute the male portion of the plant, which supplies the pollen. The fine, yellow dust is of course the pollen shed by the tassels and it will fall onto the silk of the cob, this is the female portion of the plant. If no pollen falls onto the silk, a kernel will not form.
Choose early maturing varieties and ensure that if you are growing different varieties that they are kept apart as cross-pollination can occur if they are planted together. Unless of course their maturity dates have a difference of at least 7 days. In such circumstances, when one variety is shedding pollen, the others will not be receptive to pollen.
The cobs should be ready for harvesting about three weeks after flowering finishes. The tassels will turn brown and lose much of their silkiness. Pull back the protecting green sheath and press one or two of the grains with your thumb. If they are ready they will spurt out a thick creamy juice.
As soon as the cobs are harvested, the sugars in the kernels quickly convert to starches and so they become less sweet. To ensure maximum sweetness, the cobs should be immersed in ice-cold water as soon as possible after picking and left in the water until eaten.